Never it would happens buddy, unless N. Korea do something DUMB and nazi-grade evil on CHINESES AND AMERICANS (or allies..).
For now, PRC use NK as a sort of 'buffer state' to be not in contact to allies of USA, (pure, occidental, liberal) capitalist states. Albeit North Korea start to wear their patience and embarass them I admit, but at best, I see the leaders in Beijing just saying going' ah, fuck this shit' and not helping them/dumping them the day Pyongyang need them.